Passive-active mount

• US 5,887,858 A
• Filed: 10/22/1996
• Issued: 03/30/1999
• Est. Priority Date: 10/22/1996
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Su, Jen-Houne Hannsen
• Primary Examiner(s): Graham, Matthew C.
• Application Number:
  US08/734,889
• Time in Patent Office: 889 Days
• Field of Search: 267/240.14, 267/64.24, 267/62.28, 267/122, 267/64.27, 188/374, 188/379, 188/380
• US Class Current: 267/122
• CPC Class Codes: F16F 15/02 Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems F16F15/005 takes precedence ; layered products B32B; suppression of vibration in ships B63; relieving load on bearings, using magnetic means F16C39/06
• CPC Class Codes: F16F 15/0232 with at least one gas spring F16F15/027 takes precedence
• CPC Class Codes: F16F 15/0275 Control of stiffness
• CPC Class Codes: F16F 15/08 with rubber springs grommet- or bushing-type resilient mountings F16F1/3732, F16F1/38; with springs made of rubber and metal arrangement of internal-combustion or jet-propulsion units B60K5/12; mounting of propulsion plants on vessels B63H21/30; mounting of vehicle drivers' cabs B62D33/0604
• CPC Class Codes: F16F 2230/08 Sensor arrangement

Abstract

The inventively advanced mount accommodates a conventional mount (such as an air mount) so as to include, at the mount'"'"'s foundation-securing plate, at least one motion sensor and at least one vibratory actuator. Each sensor is correlated with an actuator. For each sensor-actuator pair, the electrical feedback loop includes generation by the sensor of a signal resulting from the local vibration of the foundation-securing plate, generation by a processor/controller of a signal derived from the sensor'"'"'s signal, and exertion upon the foundation-securing plate by the sensor'"'"'s paired actuator of a vibratory force commanded by the processor/controller'"'"'s signal. Many preferred inventive embodiments collocate each sensor with its paired actuator and implement a conventional vibration suppression algorithm involving collocated velocity feedback. The inventive "passive-active" mount uniquely brings to bear, sequentially and complementarily, passive vibration control followed by active vibration control.

Claims

1. A mount suitable for passive-active vibration isolation, said mount comprising:

an upper securement member, for securement with respect to an isolated body;

a lower securement member, for securement with respect to an isolatee body;

a resilient member which is characterized by low dynamic load transmissibility, said resilient member being for passive reduction of the transmission of vibration from said upper securement member to said lower securement member;

at least one sensor coupled with said lower securement member; and

at least one actuator coupled with said lower securement member each said actuator near a corresponding said sensor;

wherein said at least one sensor and said at least one actuator are arranged in at least one collocational relationship;

wherein each said collocational relationship has associated therewith a corresponding said sensor, a corresponding said actuator and a corresponding region of said lower securement member;

wherein each said collocational relationship is characterized by approximate identity of said corresponding said sensor and said corresponding said actuator, said approximate identity being both in structural placement and functional direction; and

wherein, in accordance with each said collocational relationship;

said corresponding said sensor is capable of generating a sensor signal which is representative of the local vibration in said corresponding said region and which is representable as a control signal; and

said corresponding said actuator is capable of generating in said corresponding said region a vibratory force which;

is representative of said control signal which is representative of said sensor signal generated by said corresponding said sensor; and

actively reduces the transmission through said corresponding said region of vibration which reaches said lower securement member after having been passively reduced by said resilient member.

2. A mount as in claim 1, wherein said vibratory force effectively increases the dynamic stiffness of said isolatee body.

3. A mount as in claim 1, wherein, in accordance with each said collocational relationship, said corresponding said sensor is selected from the group consisting of accelerometer and velocity sensor.

4. A mount as in claim 1, wherein said mount is an air mount, said upper securement member includes an upper plate, said lower securement member includes a lower plate, and said resilient member includes a flexible gas-containing member.

5. A mount as in claim 4, wherein, in accordance with each said collocational relationship, said corresponding said actuator is coupled with said lower plate so as to be situated inside said flexible gas-containing member.

6. A mount as in claim 4, wherein said top plate and said bottom plate each have a substantially circular shape and an imaginary center through which said imaginary axis passes.

7. A mount as in claim 1, wherein said mount is an elastomeric mount and said resilient member includes a solid elastomeric structure.

8. A mount as in claim 7, wherein said lower securement member has a surface portion which is outside said solid elastomeric structure, and wherein, in accordance with each said collocational relationship, said corresponding said actuator is coupled with said lower securement member at said surface portion.

9. A mount as in claim 1, wherein said lower securement member is a lower plate, said lower plate has at least one recess, and, in accordance with at least one said collocational relationship, said corresponding said sensor is coupled with said lower plate at least partially within a said recess.

10. A mount as in claim 1, wherein said lower securement member is a lower plate, said lower plate has an upper surface portion, and, in accordance with each said collocational relationship, said corresponding said actuator is coupled with said lower plate at said upper surface portion.

11. A mount as in claim 1, wherein:

said resilient member is characterized by low dynamic load transmissibility of vibration in a higher frequency bandwidth;

said vibration which reaches said lower securement member has not been passively reduced in a lower frequency bandwidth; and

said vibratory force actively reduces the transmission through said corresponding said region of vibration in said lower frequency bandwidth.

12. A vibration isolator which is adapted for engagement with a processor/controller, said processor/controller being capable of generating a control signal, said vibration isolator comprising:

a spring assembly which includes a top member for securing said spring assembly with respect to an isolated entity, a bottom member for securing said spring assembly with a respect to an isolatee entity, and an interposed resilient member, wherein said resilient member has the property of Passively reducing vibration within a first frequency bandwith;

at least one sensor, each said sensor being coupled with said bottom member and being capable of generating a sensor signal which is in accordance with the vibration in a local zone of interest in said bottom member; and

at least one actuator, each said actuator being coupled with said bottom member and being collocationally paired with one said sensor so as to share approximate coincidence with respect to both physical situation and operational direction, each said actuator being capable of generating, in said local zone of interest of said sensor with which said actuator is collocationally paired, a vibratory force which is in accordance with said control signal, wherein said control signal is in accordance with said sensor signal which is generated by said sensor with which said actuator is collocationally paired, wherein said vibratory force has the tendency of actively reducing vibration within a second frequency bandwith which differs from said first frequency bandwith.

13. A vibration isolator as in claim 12, wherein said passively reducing vibration and said actively reducing vibration occur in succession.

14. A vibration isolator as in claim 12, wherein each said sensor is selected from the group consisting of accelerometer and velocity sensor.

15. A vibration isolator as in claim 12, wherein said resilient member is a pneumatic member, and each said actuator is coupled with said bottom member within said pneumatic member.

16. A vibration isolator as in claim 12, wherein said resilient member is an elastomeric member, and each said actuator is coupled with said bottom member exteriorly with respect to said elastomeric member.

17. A vibration isolator as in claim 12, wherein said bottom member includes a bottom plate having a top side, and each said actuator is coupled with said bottom plate upon said top side.

18. A vibration isolator as in claim 12, wherein said processor/controller is a PID controller.

19. Method of making a mount suitable for passive-active vibration isolation, said method comprising:

providing a passive mount having an upper securement member, a lower securement member, and a resilient member which is characterized by low dynamic load transmissibility, said resilient member being for passive reduction of the transmission of vibration from said upper securement member to said lower securement member;

coupling at least one sensor with said lower securement member; and

coupling at least one actuator with said lower securement members;

wherein said at least one sensor and said at least one actuator are arranged in at least one collocational relationship;

wherein each said collocational relationship has associated therewith a corresponding said sensor, a corresponding said actuator and a corresponding region of said lower securement member;

wherein each said collocational relationship is characterized by approximate identity of said corresponding said sensor and said corresponding said actuator, said approximate identity being both in structural placement and functional direction; and

wherein, in accordance with each said collocational relationship;

said corresponding said sensor is capable of generating a sensor signal which is representative of the local vibration in said corresponding said region and which is representable as a control signal; and

said corresponding said actuator is capable of generating in said corresponding said region a vibratory force which;

is representative of said control signal which is representative of said sensor signal generated by said corresponding said sensor; and

actively reduces the transmission through said corresponding said region of vibration which reaches said lower securement member after having been passively reduced by said resilient member.

20. Method of making a mount as in claim 19, wherein said mount is an air mount, and said resilient member includes a flexible gas-containing member.

21. Method of making a mount as in claim 19, wherein said mount is an elastomeric mount, and said resilient member includes a solid elastomeric structure.

22. Method of making a mount as in claim 19, wherein:

said resilient member is characterized by low dynamic load transmissibility of vibration in a higher frequency bandwidth;

said vibration which reaches said lower securement member has not been passively reduced in a lower frequency bandwidth; and

said vibratory force actively reduces the transmission through said corresponding said region of vibration in said lower frequency bandwidth.